background image

14

attack on ENV 2 controlling the filter from a closed 
lowpass configuration: the VCA will be 
open-and-closed again before any significant output 
is developed from the filter.

- are the oscillators tuned higher than audibility?
- is the proper assignment switch--in the 

mini-sequencer--set to keyboard control of the mod-
ule?

- if the assignment switch is not set to keyboard control, 

is the clock on or off? (No gates can be produced, of 
course, unless the clock is on.)

- how high is the sustain level on ENV 1? In legato key-

board playing, when the VCA is under control of ENV 
1, there must be some sustain voltage or the output 
of the module will disappear more or less rapidly, 
depending on the decay time setting of ENV 1. The 
same holds for the filter when its manual setting is 
closed and only ENV 2 opens it.

2. CONTINUOUS SOUND: (EITHER MODULE)

- there are really only two ways to get continuous sound 

from a module; one of them you are already familiar 
with since that's how we started you off: the VCA 
BYPASS switch on, and the filter open. If either of 
these conditions does not hold then no continuous 
sound is possible, except that

- with certain envelope settings, under gating from the 

clock, an extremely high tempo setting of the clock 
control will produce virtually continuous sound sim-
ply because of the high tempo. (Imagine playing notes 
on a piano as rapidly as possible, like a mando-
lin-"continuous sound".) Naturally this can't happen 
unless the proper assignment switch on the minise-
quencer is set for gating from the clock rather than 
the keyboard.

F. USING THE MINISEQUENCER

As you already know, the ASSIGNMENTS switches in the minise-
quencer section of your Oberheim synthesizer must be down in 
order to play the voice modules from the keyboard. In the down 
position, each module gets a keyboard control voltage, which 
controls the oscillator pitches, and a keyboard gate signal, 
which starts and stops the envelope generators.

If the assignment switch for either voice module is in either 
the middle or upper position, both the keyboard control voltage 
and the keyboard gate signal are disconnected from the module 

Summary of Contents for Two Voice

Page 1: ...A BRIEF INSTRUCTION MANUAL for the OBERHEIM TWO VOICE SYNTHESIZER prepared by james michmerhuizen director the boston school of electronic music...

Page 2: ...is on voice module two will not be gated until a second key is depressed 3 The PORTAMENTO control normally left fully counterclock wise introduces a lengthening pitch slide between different notes on...

Page 3: ...king the external connection to headphones or ampli fier you may turn the synthesizer on Locate the ASSIGNMENTS switches in the minisequencer section and be sure that they are all down In each voice m...

Page 4: ...scription following applies to the three switch version The first switch on the left selects the source of control voltages and gates for VOICE MODULE ONE In its lowest posi tion voice module one will...

Page 5: ...nt of LAG low frequency filtering applied to the sample hold voltage Turning the lag control to the right produces in other words the same effect on pitches being governed by the sample hold that the...

Page 6: ...he three position switch selects one of three control signals indicated on the panel to be routed through the rotary pot just above the switch If this knob is rotated to the right the selected control...

Page 7: ...ter begins to have some effect on a signal passing through it is called the cutoff frequency of the filter The large single knob labelled RESONANCE determines the filter resonance at its cutoff freque...

Page 8: ...ctly to the output of the NOISE GENERATOR that is part of the sample hold in the minisequencer Noise filtered in various ways is used in the production of wind thunder and motor sounds as well as many...

Page 9: ...e NOTE above In order to simplify the operation of the voice module while learning or whenever it is necessary to hear continuous sound this VCA BYPASS SWITCH can be moved to the on right position Thi...

Page 10: ...nual pulse width controls of each oscillator note that these have no effect on the sawtooth oscillator outputs and finally with the VCF manual controls for frequency resonance and pass mode Do not at...

Page 11: ...by voltage control you are changing the range or area of particular frequencies that are emphasized Try using maximum resonance with a lowpitched sawtooth input open only a little about 10 o clock an...

Page 12: ...s the filter frequency down as it is rotated to the right the ENV 2 signal drives the filter frequency up d as the filter resonance is increased its output level will generally increase Compensate by...

Page 13: ...nd sustain and fairly short decay Now slight changes in the filter frequency control in the range 12 o clock to 3 O clock will produce a wide range of percussive noises In a later section you will lea...

Page 14: ...dinary and conservative results however will come from playing con tinuous legato on the lower voice and a slight nonlegato on the upper voice E TROUBLESHOOTING I Using only the controls we have intro...

Page 15: ...t s how we started you off the VCA BYPASS switch on and the filter open If either of these conditions does not hold then no continuous sound is possible except that with certain envelope settings unde...

Page 16: ...o change the pitch of the oscillator The on off switch for the minisequencer CLOCK has also a lower position labelled step This position is spring loaded and the svitcb will not stay there but every t...

Page 17: ...nspositions will occur with the depression of only a single key if one key is held down while another is depressed to the right of it the sequence will transpose to the higher key only for as long as...

Page 18: ...trol of the s h begin with the two knobs in the s h section rotated maximum counterclockvise and slowly increase the range setting The first voice produces a series of random pitches over a wider and...

Page 19: ...all four to check 4 The beat frequency will always double as you go up by octaves So after you have tuned at 8 go up to 4 and then 2 to check on the tuning of each oscillator read just if necessary If...

Page 20: ...fective range 3 As you increase the filter resonance beyond about the eleven o clock position begin to decrease the audio input levels to the filter until at maximum resonance the audio input level s...

Reviews: